Showing papers by "Ariel E. Lugo published in 2000"

The Potential for Carbon Sequestration Through Reforestation of Abandoned Tropical Agricultural and Pasture Lands

Abstract: Approximately half of the tropical biome is in some stage of recovery from past human disturbance, most of which is in secondary forests growing on abandoned agricultural lands and pastures. Reforestation of these abandoned lands, both natural and managed, has been proposed as a means to help offset increasing carbon emissions to the atmosphere. In this paper we discuss the potential of these forests to serve as sinks for atmospheric carbon dioxide in aboveground biomass and soils. A review of literature data shows that aboveground biomass increases at a rate of 6.2 Mg ha -1 yr -1 during the first 20 years of succession, and at a rate of 2.9 Mg ha -1 yr -1 over the first 80 years of regrowth. During the first 20 years of regrowth, forests in wet life zones have the fastest rate of aboveground carbon accumulation with reforestation, followed by dry and moist forests. Soil carbon accumulated at a rate of 0.41 Mg ha -1 yr -1 over a 100-year period, and at faster rates during the first 20 years (1.30 Mg carbon ha -1 yr -1) . Past land use affects the rate of both above- and belowground carbon sequestration. Forests growing on abandoned agricultural land accumulate biomass faster than other past land uses, while soil carbon accumulates faster on sites that were cleared but not developed, and on pasture sites. Our results indicate that tropical reforestation has the potential to serve as a carbon offset mechanism both above- and belowground for at least 40 to 80 years, and possibly much longer. More research is needed to determine the potential for longer-term carbon sequestration for mitigation of atmospheric CO 2 emissions.

Hurricanes, Coral Reefs and Rainforests: Resistance, Ruin and Recovery in the Caribbean

Abstract: The coexistence of hurricanes, coral reefs, and rainforests in the Caribbean demonstrates that highly structured ecosystems with great diversity can flourish in spite of recurring exposure to intense destructive energy. Coral reefs develop in response to wave energy and resist hurricanes largely by virtue of their structural strength. Limited fetch also protects some reefs from fully developed hurricane waves. While storms may produce dramatic local reef damage, they appear to have little impact on the ability of coral reefs to provide food or habitat for fish and other animals. Rainforests experience an enormous increase in wind energy during hurricanes with dramatic structural changes in the vegetation. The resulting changes in forest microclimate are larger than those on reefs and the loss of fruit, leaves, cover, and microclimate has a great impact on animal populations. Recovery of many aspects of rainforest structure and function is rapid, though there may be long-term changes in species composition. While resistance and repair have maintained reefs and rainforests in the past, human impacts may threaten their ability to survive.

The tendency for trees to be multiple-stemmed in tropical and subtropical dry forests : Studies of Guanica forest, Puerto Rico

Abstract: Multiple-stemmed trees are a characteristic feature of Caribbean dry forests. In a semi-deciduous forest stand in Guanica Forest, Puerto Rico, 43.3% of all trees have multiple stems. These multiple-stemmed trees account for 58.0% of total basal area. Ten of eleven common species examined had examples of multiple-stemmed individuals, varying between 13.9% and 80.8% of all individuals for a given species. The presence of multiple-stemmed trees with intact (unharvested) main stems, and the occurrence of multiple-stemmed trees too small to have been subject to cutting prior to forest protection, suggest that the multiple-stemmed condition may arise in the absence of human influence. Natural mechanisms that can promote a multiple-stemmed growth form are discussed.